<template>
  <div class="goods-image">
      <!-- 放大图 -->
      <div class="large" v-show="!isOutside">
        <img
          :src="goods[activelndex]"
          alt=""
          :style="{ left: largePos.x, top: largePos.y }" />
     </div>
     <!-- 主图 -->
    <div class="middle" ref="target">
      <img
        :src="goods[activelndex]"
        alt=""
      />
      <!-- 主图上方的遮罩盒子  -->
         <div
           class="layer"
           v-show="!isOutside"
           :style="{ left: layerPos.x, top: layerPos.y }">
        </div>
    </div>
    <!-- 图片列表  -->
    <ul class="small">
      <li v-for="(item,index) in goods" :key="index">
        <img
          :src="item"
          alt=""
          @mouseenter="activelndex=index"
        />
      </li>
    </ul>
  </div>
</template>

<script>
import { reactive, ref, watch } from 'vue'
import { useMouseInElement } from '@vueuse/core'
export default {
  name: 'GoodsImage',
  props: {
    goods: {
      type: Array,
      default: () => []
    }
  },
  setup () {
    const activelndex = ref(0)
    const target = ref(null)
    // elementX/elementY    鼠标在盒子内的坐标
    // isOutside            表示目标元素外面/里面
    const { isOutside, elementX, elementY } = useMouseInElement(target)
    //    定义响应式数据，更新数据的时候更新视图
    const layerPos = reactive({ x: 0, y: 0 })
    const largePos = reactive({ x: 0, y: 0 })
    //   监听鼠标的两个坐标
    watch([elementX, elementY], () => {
    // -100 鼠标和盒子中心对齐
      let x = elementX.value - 100
      let y = elementY.value - 100
      //  上左下右边界判断
      if (x < 0)x = 0
      if (y < 0)y = 0
      if (x > 200)x = 200
      if (y > 200)y = 200
      //   遮罩贺子坐标，注意px单位
      layerPos.x = x + 'px'
      layerPos.y = y + 'px'
      //   大图坐标，-1反方向移动，2是两倍比例移动
      largePos.x = -1 * 2 * x + 'px'
      largePos.y = -1 * 2 * y + 'px'
    })
    // console.log(target)
    return { activelndex, target, isOutside, layerPos, largePos }
  }
}
</script>

<style scoped lang="less">
.goods-image {
  width: 480px;
  height: 400px;
  position: relative;
  display: flex;
   // 大图预览
   .large {
     position: absolute;
     top: 0;
     left: 412px;
     width: 400px;
     height: 400px;
     box-shadow: 0 0 10px rgba(0, 0, 0, 0.1);
     background-repeat: no-repeat;
     background-size: 800px 800px;
     background-color: #f8f8f8;
     overflow: hidden;
     z-index: 401;
     img {
       width:800px;
       height:800px;
       max-width: 800px;
       max-height: 800px;
       position: absolute;
       left: 0;
       top: 0;
     }
   }
  .middle {
    width: 400px;
    height: 400px;
    background: #f5f5f5;
    position: relative;
    cursor: move;
    .layer {
      width: 200px;
      height: 200px;
      background: rgba(0,0,0,.2);
      left: 0;
      top: 0;
      position: absolute;
    }
  }
  .small {
    width: 80px;
    li {
      width: 68px;
      height: 68px;
      margin-left: 12px;
      margin-bottom: 15px;
      cursor: pointer;
      &:hover,
      &.active {
        border: 2px solid @xtxColor;
      }
    }
  }
}
</style>
